How do I reboot my server, it's not responding?

For most servers you can login to client portal and view service details, below basic information...

 I have SPLA key for Windows, I want to use that for windows installation.

For some servers we can utilize your own key, contact our support to make arrangements.

 I need my server reinstalled

If there is no reinstall button on service page, just contact support. For dedicated seedboxes...

 Microsoft Hyper-V Server doesn't have GUI!

It's not supposed to have, it's a "free windows" for virtualization only. See...

 OS i want is not in the list! I want XYZ OS

Ask from Support. At times we can accomodate you, but not always.

 What's the SSH details for my windows server?

There is no SSH server for Windows servers. Windows servers are generally managed via RDP.